package net.xdclass.util;

import com.fasterxml.jackson.databind.ObjectMapper;
import lombok.extern.slf4j.Slf4j;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintWriter;
import java.net.InetAddress;
import java.net.UnknownHostException;
import java.security.MessageDigest;
import java.util.Random;
import java.util.UUID;

/**
 * @Classname CommonUtil
 * @Description TODO
 * @Date 2022/4/7 10:54
 * @Created by sunhao
 */
@Slf4j
public class CommonUtil {

  /**
   * 获取ip
   *
   * @param request
   * @return
   */
  public static String getIpAddr(HttpServletRequest request) {
    String ipAddress = null;
    try {
      ipAddress = request.getHeader("x-forwarded-for");
      if (ipAddress == null || ipAddress.length() == 0 || "unknown".equalsIgnoreCase(ipAddress)) {
        ipAddress = request.getHeader("Proxy-Client-IP");
      }
      if (ipAddress == null || ipAddress.length() == 0 || "unknown".equalsIgnoreCase(ipAddress)) {
        ipAddress = request.getHeader("WL-Proxy-Client-IP");
      }
      if (ipAddress == null || ipAddress.length() == 0 || "unknown".equalsIgnoreCase(ipAddress)) {
        ipAddress = request.getRemoteAddr();
        if (ipAddress.equals("127.0.0.1")) {
          // 根据网卡取本机配置的IP
          InetAddress inet = null;
          try {
            inet = InetAddress.getLocalHost();
          } catch (UnknownHostException e) {
            e.printStackTrace();
          }
          ipAddress = inet.getHostAddress();
        }
      }
      // 对于通过多个代理的情况，第一个IP为客户端真实IP,多个IP按照','分割
      if (ipAddress != null && ipAddress.length() > 15) {
        // "***.***.***.***".length()
        // = 15
        if (ipAddress.indexOf(",") > 0) {
          ipAddress = ipAddress.substring(0, ipAddress.indexOf(","));
        }
      }
    } catch (Exception e) {
      ipAddress = "";
    }
    return ipAddress;
  }


  /**
   * 获取随机数
   * @param length 长度
   * @return
   */
  public static String getRandomCode(int length) {
    String source = "0123456789";
    Random random = new Random();
    StringBuilder sb = new StringBuilder();
    for (int i = 0; i < length; i++) {
      sb.append(source.charAt(random.nextInt(9)));
    }
    return sb.toString();
  }

  /**
   * md5加密
   * @param data
   * @return
   */
  public static String MD5(String data) {
    try {
      java.security.MessageDigest md = MessageDigest.getInstance("MD5");
      byte[] array = md.digest(data.getBytes("UTF-8"));
      StringBuilder sb = new StringBuilder();
      for (byte item : array) {
        sb.append(Integer.toHexString((item & 0xFF) | 0x100).substring(1, 3));
      }

      return sb.toString().toUpperCase();
    } catch (Exception exception) {
    }
    return null;
  }

  /**
   * 获取32位UUID
   */
  public static String  generateUUID(){
    return UUID.randomUUID().toString().replaceAll("-","").substring(0,32);
  }

  /**
   * 获取时间戳
   */
  public static long getCurrentTimestamp(){
    return System.currentTimeMillis();
  }

  /**
   * 生成指定长度随机字母和数字
   *
   * @param length
   * @return
   */
  private static final String ALL_CHAR_NUM = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
  public static String getStringNumRandom(int length) {
    //生成随机数字和字母,
    Random random = new Random();
    StringBuilder saltString = new StringBuilder(length);
    for (int i = 1; i <= length; ++i) {
      saltString.append(ALL_CHAR_NUM.charAt(random.nextInt(ALL_CHAR_NUM.length())));
    }
    return saltString.toString();
  }


  /**
   * 响应json数据给前端
   */
  public static void sendJsonMessage(HttpServletResponse response,Object obj){
    ObjectMapper objectMapper = new ObjectMapper();

    response.setContentType("application/json; charset=utf-8");

    try(PrintWriter writer = response.getWriter()) {
      writer.print(objectMapper.writeValueAsString(obj));
      response.flushBuffer();
    }catch (Exception e){
      log.warn("响应json数据失败!");
    }
  }

  public static void writeData(HttpServletResponse response, JsonData jsonData) {
    try {
      response.setContentType("text/html;charset=UTF8");
      response.getWriter().write(jsonData.getData().toString());
      response.getWriter().flush();
      response.getWriter().close();
    } catch (IOException e) {
      log.error("写出Html异常:{}", e);
    }
  }
}
